The production of hydrogen is becoming quite desirable since hydrogen has beneficial aspects as a direct heating fuel or as a means for generating electrical energy in a fuel cell. Consequently, substantial efforts have been devoted to obtaining large volumes of hydrogen for subsequent use in heat or electrical energy generation. At this time, the most common method of producing hydrogen is electrolysis of water, which consumes a substantial amount of electrical energy since it requires over 2.0 volts D.C. for decomposition. As is well known, the higher the voltage necessary for electrolysis, the higher the electrical energy cost for the process. To reduce the cost of production of hydrogen, most efforts have been directed toward modifying the water electrolysis process in a manner to reduce the voltage required for the hydrolysis and, thus, the electrical energy required. For instance, it has been suggested that high pressure water electrolysis cells can be developed which will reduce the voltage from slightly over 2.0 volts to the general range of about 1.6-1.7 volts. Still, the production of hydrogen by the electrolysis of water will involve a substantial electrical energy input which will continue to render hydrolysis of water for the production of hydrogen an expensive process even though it may be commercially feasible in view of the versatility of the generated hydrogen.
The present invention relates to a novel method of producing hydrogen by electrolysis in a cell using a halogen acid such as hydrochloric acid, hydrobromic acid or hydriodic acid. In this manner, the electrolysis voltage can be reduced and the required electrical energy for the electrolysis process can be made lower than even the proposed improved processes for water electrolysis.
The electrolysis of halogen acid to produce hydrogen and the constituent halogen is a well known technology. This concept is shown in U.S. Pat. Nos. 603,058; 1,746,542; 3,236,760; 3,242,065 and 3,756,930. The present invention does not involve, as a novel feature, the concept of obtaining hydrogen from the electrolysis of the halogen acid; however, the invention relates to this general field and develops a novel method wherein this electrolysis process can be used for economic creation of hydrogen at a cost substantially below the cost of water electrolysis. Consequently, the invention relates to a method wherein the halogen acid electrolysis concept can be employed for the production of commercial quantities of hydrogen with an overall efficiency heretofore not obtainable. As will be described with respect to the present invention, the invention involves the concept of employing the electrolysis of the halogen acid in combination with a method of producing the acid in an efficient manner, which results in a sufficient quantity of the acid created at a low cost factor. The process is performed in a unit or device involving both the electrolysis cell and the acid forming reaction area which may be in the electrolysis cell itself or communicated therewith by conduits through which the halogen acid for the electrolysis process is circulated in liquid or gaseous form.
In summary of the background, the present invention relates to an improvement in producing hydrogen by employing the halogen acid electrolysis concept with a novel interacting and combined halogen acid producing concept.